In a last ditch effort to defeat Tirek, Twilight loses everything she held dear.
Existence is such a fickle thing. It's definition warped and deformed. So easily revoked by the will of another. Twilight Sparkle is due for a lesson no God could prepare her for.
Fate is a matter of whimsy, and destiny is as fickle as she is cruel. Twilight Sparkle- but a filly- will learn this in the worst way possible.